1. Field of the Invention
The present invention relates to a flow shut off or throttling valve in the nozzle housing of a sprinkler for limiting or preventing flow of water to the nozzle.
2. Background of the Invention
In order to achieve suitably irrigate an irregularly shaped area of land surface or near the borders of a land parcel, it may be desirable to change the distribution profile or configuration in a sprinkler to adjust the coverage range, distribution angle, etc. As a result, several different types of sprinklers have been offered to address this need.
For example, U.S. Pat. Nos. 3,323,725 to Hruby; 3,383,047 to Hauser; and 4,729,511 to Citron each discloses a sprinkler having various structures for restricting a flow of water through the flow path through the sprinkler. However, restriction of the flow also results in a loss in pressure of the flow exiting from the nozzle. Such limited adjustment capabilities, moreover, are frequently inadequate to provide adequate or even coverage to edges, corners, or more unusual boundaries of a parcel of land to be irrigated.
U.S. Pat. No. 5,234,169 to McKenzie, on the other hand, discloses a sprinkler which provides a removable nozzle and a camming mechanism for expelling the nozzle from the flow passage in a nozzle housing. It is thus possible to achieve a greater range of distribution profiles with the ability to change the nozzle altogether, relative to the sprinkler systems in the prior art referenced above. With this sprinkler, however, it is necessary to turn off a flow of water to the sprinkler in order to avoid getting wet during the nozzle exchange process.
Similarly, U.S. Pat. No. 6,085,995 to Kah, Jr. et al. discloses a sprinkler in which a plurality of different nozzles are provided in the nozzle housing, with each nozzle effecting a different distribution profile from the others. A nozzle selection change is easily performed by operating a selection mechanism provided on the nozzle housing. With this sprinkler, however, the plurality of nozzles are provided on a common unit, and a user may not need all of the different types of nozzles provided in the set.
In U.S. Pat. No. 5,762,270 to Kearby, et al, the disclosed sprinkler unit includes a valve provided in the flow path through the sprinkler housing for stopping the flow through the nozzle for facilitating a nozzle change. The valve, however, is physically disposed within the flow path, regardless of whether the valve is in an opened position or a closed position. Such placement of the valve requires the flow stream to flow around the valve enroute to the nozzle when the valve is open, thus resulting in increased turbulence in the flow stream and pressure loss of the flow exiting from the nozzle.
It is thus desirable to provide a sprinkler having a removable nozzle and a mechanism for stopping the flow through the nozzle at the sprinkler location, wherein the presence of the mechanism does not introduce a pressure loss to the flow exiting the sprinkler.